English

Two-Pion Exchange Contributions to the Nucleon-Nucleon Interaction from the Roper Resonance

Nuclear Theory 2026-03-02 v2

Abstract

We derive the long-range components of the nucleon-nucleon (NN) two-pion-exchange potential with an intermediate Roper resonance. Leading-order interactions in heavy-baryon chiral perturbation theory are considered. NN phase shifts with orbital angular momentum L2L\geq 2 are calculated in first-order perturbation theory and compared to those obtained without the Roper resonance. We show that the Roper contribution is sizeable for DD waves and improves the description of phase shifts for all the partial waves slightly. We also discuss the role of the Roper resonance in the NN interaction in the framework of resonance saturation.

Keywords

Cite

@article{arxiv.2602.11815,
  title  = {Two-Pion Exchange Contributions to the Nucleon-Nucleon Interaction from the Roper Resonance},
  author = {Yang Xiao and Li-Sheng Geng and U. van Kolck},
  journal= {arXiv preprint arXiv:2602.11815},
  year   = {2026}
}

Comments

We correct a factor in the triangle-diagram contribution and update the corresponding expressions